Especially when they have 50 years of accumulated dust/oil/crud. Main hands. Minute Recorder Hand and Minute hand. As you can see, they are rather dirty and have slight corrosion blisters along the edges. They're from a Landeron based chrono I'm servicing and when I went to put them back on I checked them out and went "Ugh!, no way!". So how do you clean hands as delicate and rare as these. The risks associated with mechanical cleaning were too great, so my solution was a solution, Town Talk Silver Cleaning Solution in fact. I had a 100ml tube jar and filled it with the cleaner, placed the hands into the jar and put it in the ultrasonic bath for 5 minutes. Then the solution was poured off and successive fills of distilled water added and allowed to rinse off the solution. The whole lot was then poured gently into a 125micron funnel filter, then laid on a Kimwipe to dry in the sun. This is the crud trapped in the filter. I think they turned out quite well. My next big decision. Do I attempt to clean the dial. From arm's length it looks OK, but under a scope it looks pretty bad. If I knew most of the spots and blemishes would come off I'd try the cleaning solution, but I'm not sure so I think I'll just have to live with a soft brush and a puffer to clean it up.